Absorbent article with surface structure

ABSTRACT

There is disclosed an absorbent article including: a surface structure having a liquid-permeable surface sheet located on a liquid-receiving side; a back sheet; and an absorbent core sandwiched between the surface structure and the back sheet. In an area including at least a centerline extending in a longitudinal direction of the absorbent article, the surface sheet is corrugated to form recesses and ridges extending in the longitudinal direction and alternating with each other in a transverse direction perpendicular to the longitudinal direction. The ridges are given an elastically shrinking function in the longitudinal direction at least at their crests or vicinities thereof so that the surface structure is formed into a curved shape. The surface structure thus curved can fit the shape of a crotch. Therefore, the liquid is hard to flow in the transverse direction to prevent the leakage.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an absorbent article such as adisposable diaper, a pad for the incontinence of urine or a sanitarynapkin and, more particularly, it relates to an absorbent articleincluding a surface structure having an excellent fittingness on a body.

[0003] 2. Related Art

[0004] The absorbent article of the prior art such as the disposablediaper, the pad for the urinary incontinence or the sanitary napkingenerally includes: a liquid-permeable top sheet disposed on theliquid-receiving, inner side; a liquid-impermeable back sheet disposedon the outer side; and an absorbent core made of pulp and a highlyabsorbent polymer (or super absorbent polymer: SAP) and sandwichedbetween the two sheets.

[0005] In such an absorbent article, a structure has been investigatedfor improving the fittingness on a urinary organ and thereabout, whenapplied to a crotch, to prevent excreted liquid such as urine ormenstrual blood from leaking transversely. For example, there has beenpracticed a structure, in which a relatively bulky cushion layer made ofa hydrophilic fiber layer is disposed on the liquid-receiving side ofthe absorbent core, or a structure in which an absorbent material layersmaller than the absorbent core is disposed on the liquid-receiving sideof the absorbent and such a cushion layer as above is further disposedon the absorbent material layer. In another structure, gathers forpreventing the transverse leakage are disposed on two side edges of theabsorbent core.

[0006] However, the aforementioned absorbent article provided with thecushion layer cannot cover the individual differences in the shape ofthe crotch reliably at all times. Especially, the disposable diaper orthe pad for the urinary incontinent for taking care of old peoplefrequently fails to fit the crotch. This is because the old people areseriously different among the individuals in the width of the crotch, inthe flesh of the crotch, abdomen or hip or in the flabbiness or wrinklesof the skin, as compared with infants. If the absorbent article fails tofit the crotch, the excreted liquid will easily leak along the skin tothe outside of the absorbent article to wet the wears or bedclothes.This problem is more serious for the old people who excrete far moreliquid for one piss than the infants. When such an absorbent articleunfitted for the crotch is worn, moreover, irregular wrinkles are formedon the liquid-receiving side of the absorbent article to make it harderfor the absorbent article to absorb the excreted liquid.

[0007] Against these problems, there exists an absorbent article whichis curved to fit the crotch by providing transverse leakage preventinggathers on two side edges of an absorbent core so that the absorbentcore may follow the gathers. However, even in this absorbent article,because the central portion of the absorbent core is less curved thanthe side edges thereof, the absorbent core is difficult to fit the wholecrotch, thereby to leave gaps between the absorbent core and the crotch.As a result, a large amount of excreted liquid may move transverselythrough the gaps so that its leakage cannot be prevented by thetransverse leakage preventing gathers.

SUMMARY OF THE INVENTION

[0008] The present invention is to solve the problems of the prior artthus far described and has an object to provide an absorbent article inwhich a surface structure disposed on the liquid-receiving side easilyfits the crotch, the urinary organ or the inguinal region.

[0009] Another object of the invention is to provide an absorbentarticle which is so curved as to easily fit the crotch of the wearerthereby to prevent the transverse leakage of the excreted liquid.

[0010] According to an aspect of the invention, there is provided anabsorbent article comprising: a surface structure having aliquid-permeable surface sheet located on a liquid-receiving side; aback sheet; and an absorbent core sandwiched between the surfacestructure and the back sheet, wherein, in an area including at least acenterline extending in a longitudinal direction of the absorbentarticle, the surface sheet is corrugated to form recesses and ridgesextending in the longitudinal direction and alternating with each otherin a transverse direction perpendicular to the longitudinal direction,and the ridges are given an elastically shrinking function in thelongitudinal direction at least at their crests or vicinities thereof sothat the surface structure is formed into a curved shape.

[0011] With the surface structure of the absorbent article of theinvention, the surface sheet constructing the surface structureelastically shrinks in the longitudinal direction so that the surfacestructure is curved. As a result, the absorbent article is curved in itsentirety so that the liquid-receiving side easily fits the crotch, theabdomen or the back (or hip). Therefore, the excreted liquid can bequickly absorbed by the absorbent article while being prevented fromleaking transversly. To give the elastically shrinking function,preferably, elastic members extending in the longitudinal direction areattached to the crests of the ridges of the surface sheet.

[0012] Moreover, because the ridges thus formed have degrees of freedomagainst the vertical and horizontal pressures i.e., because they can beflexibly deformed, the ridges can fit the roughness of the urinaryorgan, the crotch or the inguinal region. In other words, the surfacestructure comes into contact with the wearer's body to have a largercontact area for eliminating gaps between the absorbent article and thewearer's body. As a result, the excreted liquid is prevented fromflowing transversely in such gaps and its leakage is further reduced.

[0013] Preferably, the surface structure further includes aliquid-permeable support sheet located between the surface sheet and theabsorbent core, and the support sheet is bonded to the surface sheet atan interval in the transverse direction to thereby form the recesses. Inthis case, more preferably, a cushion layer is provided inside of theridges such that the cushion layer is sandwiched between the surfacesheet and the support sheet.

[0014] Preferably, ridges in a center region including thelongitudinally extending centerline are different in height from otherridges in two side regions outside of the center region.

[0015] Preferably, cover sheets are provided to cover longitudinal endportions of the ridges.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0016]FIG. 1 is a partially sectional, perspective view showing anabsorbent article according to a first embodiment of the invention;

[0017]FIG. 2 is a sectional view of the absorbent article shown in FIG.1;

[0018]FIG. 3 is an explanatory view showing a curved state of a surfacestructure of the invention;

[0019]FIG. 4 is a partially sectional, perspective view showing anabsorbent article according to a second embodiment of the invention;

[0020]FIG. 5 is a sectional view showing an absorbent article accordingto a third embodiment of the invention;

[0021]FIG. 6 is a sectional view showing an absorbent article accordingto a fourth embodiment of the invention;

[0022]FIG. 7 is a top plan view showing an example in which a disposablediaper is constructed of the absorbent article of the invention;

[0023]FIG. 8 is a perspective view showing an absorbent articleaccording to a fifth embodiment of the invention;

[0024]FIG. 9 is a (transversely) sectional view of the absorbent articleof FIG. 8; and

[0025]FIG. 10 is a (longitudinally) sectional view of the absorbentarticle of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026]FIG. 1 is a partially sectional, perspective view showing anabsorbent article according to a first embodiment of the invention; FIG.2 is a sectional view of the absorbent article of the invention; andFIG. 3 is an explanatory view showing a state in which a surfacestructure is curved. In the following, a direction X is a transverse (orwidthwise) direction of the absorbent article, and a direction Y is alongitudinal (or lengthwise) direction of the absorbent article.

[0027] As shown in FIGS. 1 and 2, an absorbent article 1 is backed on aback side of an absorbent core 2 with a back sheet 3 and is surfaced ona liquid-receiving side of the absorbent core 2 with a surface structure4. This surface structure 4 includes a surface sheet 5 and a supportsheet 6, and these surface sheet 5 and support sheet 6 and the backsheet 3 are adhered together with an adhesive such as hot melt adhesivein a peripheral region A where no absorbent core 2 is present. When thesurface sheet 5, the support sheet 6 and the back sheet 3 containthermoplastic fibers, they may be thermally fused together in theaforementioned peripheral region A. Alternatively, it may be possiblethat only the support sheet 6 and the back sheet 3 are bonded (adheredor fused) together in the peripheral region A, while the surface sheet 5is bonded to the support sheet 6 at a position inside of the peripheralregion A (i.e. at a positon where the absorbent core 2 is present).

[0028] The absorbent core 2 is constructed by enveloping eitherpulverized pulp or a mixture of pulverized pulp and highly absorbentpolymer (or super absorbent polymer: SAP) with an absorbent sheet suchas tissue paper. The SAP can be made of polyacrylic acid, sodiumpolyacrylate, polyacrylamide, polyacrylonitrile, polyvinyl alcohol, anadditional polymer of maleic anhydride, a polyether, a condensedpolymer, a polysaccharide such as starch or cellulose, a protein such ascollagen, or the like. Examples of the SAPs include: a cross-linkedcompound of sodium polyacrylate, a graft copolymer of starch havingsodium polyacrylate or a graft copolymer of cellulose havingpolyacrylonitrile chains. The back sheet 3 may be liquid-impermeable andmade of, for example, an olefin resin sheet. When the absorbent article1 is used as a disposable diaper or sanitary napkin, the back sheet 3 ispreferably made gas-permeable. However, the back sheet 3 of theabsorbent article 1 of the invention may be made liquid-permeable, if itis used to be worn inside another absorbent material in which excessiveliquid will permeate and will be absorbed.

[0029] The aforementioned surface sheet 5 and support sheet 6 composingthe surface structure 4 are preferably made of a point-bond,air-through, spun-bond or spun-lace non-woven fabric. This non-wovenfabric is formed of, for example, hydrophilized hydrophobic fibers orhydrophilic fibers. The “hydrophilized hydrophobic fibers” as usedherein means hydrophobic fibers subjected to hydrophilic treatment. Inthis hydrophilic treatment, a hydrophobic fiber is made hydrophilic bytreating it with a surfactant; by chemically binding a chemicalsubstance such as a monomer or a polymer having a hydrophilic groupthereto; by subjecting it to plasma processing; by kneading it with achemical substance having a hydrophilic group; or by treating itssurface to have a profiled section. The surface sheet 5 and supportsheet 6 may be made of a resin film having a number of apertures. Thisresin film can be made of polyethylene (PE) or the like.

[0030] As in FIG. 2, the surface sheet 5 is bonded to the support sheet6 at an interval (or pitch distance) 7 p in the transverse direction.These bonded portions are designated by 7 a. By forming these bondedportions 7 a, the surface sheet 5 is corrugated to have recesses 7 andridges 8. That is, the surface sheet 5 is deformed to have the ridges(or bulges) 8 rising toward the wearer, between the bonded portions 7 a.The ridges 8 and the recesses 7 are extended in the longitudinaldirection (or the direction Y) to form a plurality of parallel rows. Thebonding between the surface sheet 5 and the support sheet 6 for formingthe recesses 7 can be performed by adhesion with an adhesive such as hotmelt adhesive. Alternatively, the surface sheet 5 and the support sheet6 may be thermally fused together when they contain thermoplasticfibers.

[0031] The bonded portions 7 a may be formed in longitudinallycontinuous lines. Alternatively, they may be formed to extendintermittently in the longitudinal direction. For example, if anadhesive of the hot melt type is applied to the surface of the supportsheet 6 in a spiral pattern or the like and the surface sheet 5 isadhered to the support sheet 6, the bonded portions 7 a can be formedintermittently in the longitudinal direction as above. When the bondedportions 7 a are thus intermittently formed, the excreted liquid such asurine fed to the recesses 7 readily penetrates from the bottoms of therecesses 7 into the absorbent core 2.

[0032] At the crests 8 t of the ridges 8, there are arranged elasticmembers 10, each extending in the longitudinal direction. These elasticmembers 10 are adhered to the inner side of the surface sheet 5, i.e.,to the face of the surface sheet 5 on the side of the absorbent core 2,while being elongated (or pulled and stretched) in the longitudinaldirection. Therefore, after such adhesion, the surface sheet 5longitudinally shrinks at the crests 8 t owing to the elasticallyshrinking function of the elastic members 10, so that the whole surfacestructure 4 is curved as shown in FIG. 3. As a result, the absorbentcore 2 is also curved.

[0033] The elastic members 10 may be made of any elastic material suchas natural rubber, synthetic rubber or stretch non-woven fabric (i.e.,non-woven fabric having elasticity).

[0034] Here, the surface sheet 5 per se may be made of such stretchnon-woven fabric to have an elastically shrinking function in thelongitudinal direction. In this case, the elastic members 10 need not beprovided to the surface sheet 5. Therefore, the surface structure 4 canbe easily manufactured.

[0035] The height of the ridges 8, that is, the height size 8 h (asreferred to FIG. 2) from the surface of the support sheet 6 to thecrests 8 t of the ridges 8 is preferably from 5 mm or more to 50 mm orless. Within this range, the liquid-receiving side of the absorbentarticle can fit the crotch of a wearer, even if the absorbent article isused for taking care of old people who are seriously different among theindividuals in body contours. More preferably, the height size 8 h isfrom 10 mm or more to 30 mm or less.

[0036] In the surface structure 4, moreover, there may be provided acushion layer 9 of a hydrophilic material inside of the ridges 8, i.e.,between the surface sheet 5 and the support sheet 6, as shown in FIGS. 1and 2. With this cushion layer 9, the elastcity of the ridges 8 is soenhanced that the shape of the ridges 8 can be maintained securely whenthey come into contact with the wearer. In this case, therefore, thesurface structure 4 will fit the crotch more closely. In stead ofproviding the cushions layer 9, however, the inside of the ridges 8 maybe vacant. That is, the space between the surface sheet 5 and thesupport sheet 6 may be left as clear gaps.

[0037] The hydrophilic material for the cushion layer 9 can beexemplified by various materials. For example, use can be made ofhydrophilized hydrophobic fibers of polyethylene, polypropylene, nylonor polyester, hydrophilized hydrophobic composite fibers of polyesterand polyethylene, or hydrophilic fibers such as rayon. As describedbefore, the term “hydrophilized hydrophobic fibers” means hydrophobicfibers subjected to hydrophilic treatment. Such fibers may be longfibers (or filaments) prepared in the form of tow. Or else, use can bemade of a split yarn or strip-shaped materials, which are originallyhydrophilic or originally hydrophobic but subjected to hydrophilictreatment. The split yarn is produced by finely cutting a resin filminto the net-like shape, in which short fibers extend generally in onedirection. The strip-shaped materials are produced by cutting a resinfilm or non-woven fabric into strips. Alternatively, the material may beexemplified by either a non-woven fabric, such as air-through non-wovenfabric of hydrophilic fibers or hydrophobic fibers subjected tohydrophilic treatment, which is bulky and has a low density, or a web ofopened fibers having a relatively short length (e.g., hydrophilic fibersor hydrophobic fibers subjected to hydrophilic treatment). Preferably,the cushion layer 9 is bulky and readily permeable to liquid and can bereadily elastically recovered (or restored) from its pressurized state.Therefore, it is preferable that the cushion layer 9 has a density of0.4 g/cm³ or less and the fibers constituting the cushion layer 9 has afineness of 1 denier or more.

[0038]FIG. 4 is a perspective view showing an absorbent article 1B of asecond embodiment of the invention. In this absorbent article 1B, theridges 8 are made different. Hereinafter, the detailed description ofthe portions having the same constructions as those of the firstembodiment will be omitted by designating them by the common referencenumerals.

[0039] In the embodiment shown in FIG. 4, the ridges 8 are made higher,as indicated by 8 a, in the vicinity of the central region and madelower, as indicated by 8 b, in the two side regions. Thus, thefittingness on the crotch or urinary organ is further enhanced by thedifference of the height between the ridges 8 a and 8 b. In this case,the ridges 8 a preferably have a height of about 25 mm whereas theridges 8 b preferably have a height of about 15 mm. This embodiment maybe modified such that the ridges are gradually lowered from ridges 8 cand 8 c in the central region to ridges 8 d and 8 d in the two sideregions.

[0040] On the contrary, the ridges 8 a in the vicinity of the centralregion may be made lower whereas the ridges 8 b in the two side regionsmay be made higher. In this case, the ridges 8 a preferably have aheight of about 5 mm whereas the ridges 8 b preferably have a height ofabout 15 mm. Alternatively, the ridges 8 may be made gradually higherfrom the central region to the two side regions.

[0041]FIG. 5 is a sectional view showing an absorbent article 1C of athird embodiment of the invention. In FIG. 5, two elastic members 10 aand 10 b are disposed at the crest 8 t of each ridge 8. Between twoadjacent ridges 8 and 8, on the other hand, two bonded portions 7 a and7 a are provided to form one recess 7. That is, in each recess 7, twocontinuous or intermittent lines of the bonded portions 7 a extendparallel to each other.

[0042]FIG. 6 is a sectional view showing an absorbent article 1D of afourth embodiment of the invention. In this embodiment, the ridge 8 isprovided with additional inner ridges.

[0043] In this absorbent article 1D, a second surface sheet 15 having aliquid permeability is disposed on the inner side of the surface sheet 5to form the inner ridges. Moreover, the elastic members 10 are disposedon the inner side of the second surface sheet 15, not on the inner sideof the first surface sheet 5, i.e., at the crests of the inner ridgesformed of the second surface sheet 15. With the second surface sheet 15,the cushioning properties of the surface structure 4 can be so enhancedwithout the aforementioned cushion layer 9 as to ensure a soft fittingon the crotch. In addition, the second surface sheet 15 functions as aliquid stopping layer for stopping liquid from flowing in the transversedirection. The second surface sheet 15 is formed of a resin film or ahydrophobic non-woven fabric having a plurality of apertures at a rateof aperture area of 30 to 50%, for example.

[0044] Here, the elastic members 10 may be disposed at the crests of theouter ridges of the first surface sheet 5, as in the first embodiment.It is also possible that the second surface sheet 15 per se is made ofstretch non-woven fabric having the elastically shrinking function inthe longitudinal direction while eliminating the elastic members 10. Inthis case, the first surface sheet 5 need not have the elasticallyshrinking function.

[0045]FIG. 7 is a top plan view showing an open type disposable diaperwith its liquid-receiving side being located on this side, as a specificembodiment of the absorbent article 1, 1B, 1C or 1D of the invention.

[0046] The disposable diaper, as constructed of the absorbent article ofthe invention, has an intermediate portion 21 to be applied to thecrotch of a wearer; a front portion 22 to be applied to the abdomenthereof, and a rear portion 23 to be applied to the hip thereof.

[0047] In the disposable diaper shown in FIG. 7, the back sheet 3 andthe support sheet 6 are given an hour glass shape, and the absorbentcore 2 (indicated by dotted lines in FIG. 7) is also given an hour glassshape. The transversely constricted portions of those hour glass shapesprovide the aforementioned intermediate portion 21. In the peripheralregion A where the absorbent core 2 is not present, the support sheet 6and the back sheet 3 are bonded to each other to secure the absorbentcore 2 therebetween.

[0048] In the disposable diaper shown in FIG. 7, the surface sheet 5shown in FIGS. 1 and 2 is present only in the widthwise center on theliquid-receiving side to form the ridges 8 and the recesses 7. Thecushion layer 9 may or may not be disposed between the surface sheet 5and the support sheet 6.

[0049] The area where the ridges 8 and the recesses 7 are present is ina rectangular shape extending from the front portion 22 through theintermediate portion 21 to the rear portion 23 in the longitudinaldirection and over two side regions 31 and 31 across a centerline 30 inthe transverse direction. That is, as shown in FIG. 7, the ridges 8 andthe recesses 7 are present in the area having a length almost equal tothat of the absorbent core 2 and a width almost equal to that of theintermediate portion 21 of the absorbent core 2. The area may bemodified variously according to the applications. In the disposablediaper of FIG. 7, the crests 8 t of the ridges 8 of the surface sheet 5are provided with the elastic members 10 for allowing the disposablediaper to be curved in its entirety by their elastic shrinking forces.

[0050] The elastic members 10 may be provided either all over the ridges8 in the longitudinal direction or only over the intermediate portion 21in the longitudinal direction. It may be also possible that not all butsome of the ridges 8 are provided with the elastic members 10.

[0051] In order to make the curvature of the surface structure properfor the invention, the elastic members 10 are preferably provided overat least 10% of the entire length L1 of the absorbent article 1.However, the elastic members 10 should not be limited to a continuouslength of 10% or more but may be provided partially, for example, at twoportions of 5% or more of the entire length L1. The portion requiringthe curvature is different for targets of application. For a baby orchild, for example, it is preferable that not only the intermediateportion 21 but also both the front portion 22 and the rear portion 23are curved to fit the round abdomen and hip. For an old wearer, thefront portion 22 need not be curved. Thus, the portion to be curved isproperly adjusted.

[0052] The ridges 8 of the surface structure 4 are covered at theiropposite end portions 8 e and 8 e with cover sheets 11 and 11, as shownin FIG. 7. Preferably, each cover sheet 11 has a width larger than thatof the area where the ridges 8 are formed, and is bonded to the supportsheet 6 with a C-shaped bonded portion 11 b to be opened toward theintermediate portion 21. That is, for forming a pocket, it is preferablethat each cover sheet 11 is not bonded to the support sheet 6 on theside of the intermediate portion 21.

[0053] When the excreted liquid moves along the ridges 8, it flows tothe front portion 22 or the rear portion 23 of the absorbent article 1and may further flow to the end portions 1 e and 1 e of the absorbentarticle 1. With the cover sheets 11, however, the longitudinal flows arestopped and sealed by the pockets so that no excreted liquid leaks fromthe end portions 8 e of the ridges 8. Moreover, the cover sheets 11 hidethe end portions 8 e of the ridges 8 to provide a beautiful appearance.The cover sheets 11 are preferably made of a hydrophobic sheet having abasis weight (This may be referred to as “METSUKE” in Japanese measuringunit) of 20 g/m² or more, such as a spun-bond non-woven fabric, apoint-bond non-woven fabric, a non-woven fabric laminated withpolyethylene, or a film.

[0054]FIG. 8 is a perspective view showing a urine absorbing pad for anincontinent patient or old wearer (or absorbent article 1E), as aspecific example of the absorbent article of the invention; FIG. 9 is atransverse section of FIG. 8; and FIG. 10 is a section taken in thelongitudinal direction. The urine absorbing pad shown in FIG. 8 ispreferably used for a female wearer, and is used on the inner side of anouter wear material such as disposable diaper or underwear.

[0055] This urine absorbing pad is constructed, as shown in FIG. 9, ofthe back sheet 3, the surface structure 4 and the absorbent core 2sandwiched therebetween. The absorbent core 2 is formed by enveloping amixture of pulverized pulp and highly absorbent polymer (or SAP) with atissue paper 2 a.

[0056] The ridges 8, as formed of the surface sheet 5 of the surfacestructure 4, are extended longitudinally of FIGS. 8 and 10 almost overthe full length of the urine absorbing pad and are covered at their endportions with the cover sheets 11 and 11. These cover sheets 11, thesupport sheet 6 and the back sheet 3 are bonded to one another in theperipheral region A having no absorbent core 2. The cover sheets 11 formthe pockets as in the absorbent article shown in FIG. 7.

[0057] This urine absorbing pad is wholly curved, as shown in FIG. 10,to fit along the crotch of the wearer by the elastic members 10 providedin the ridges 8. As a result, a number of wrinkles are formed on thesurfaces of the ridges 8.

[0058] Adjacent to the ridges 8 in the transverse direction, inaddition, there are formed stereoscopic gathers 16 and 16 for preventingthe transverse leakage. With these stereoscopic gathers, it is possibleto further prevent the transverse leakage of the excreted liquid. Thesestereoscopic gathers 16 and 16 are formed of liquid-impermeable sheetsinto the shape of band (or wall) which are provided with elastic members17 and 17, on their upper side edges thereof, and are bonded to theupper face of the support sheet 6, on their lower side edges. Thus, theabsorbent article 1E is provided with the stereoscopic gathers 16 and 16which rise toward the wearer. Here, longitudinal end portions of thestereoscopic gathers 16 and 16 are hidden like the end portions of theridges 8 by the cover sheets 11 and 11.

[0059] Here, the absorbent article of the invention can be used as notonly a disposable diaper and an incontinent pad but also a sanitarynapkin. In this case, the entire shape of the absorbent article can bevariably modified according to the applications. For example, it may bemodified to have a rectangular top plan shape.

[0060] As has been described hereinbefore, the absorbent article of theinvention can bring its surface structure into close contact with thecrotch to prevent the leakage. Moreover, the absorbent article havingthe ridges of the invention can be freely deformed according to theindividual differences of the crotch so that it can fit the skin of thewearer to prevent the leakage more.

[0061] In the foregoing specification, the invention has been describedin relation to preferred embodiments and many details have been setforth for the purpose of illustration. It will be apparent to thoseskilled in the art that the invention is susceptible to additionalembodiments and that certain of the details described herein can bevaried considerably without departing from the basic principles of theinvention.

[0062] Further, ‘comprises/comprising’ when used in this specificationis taken to specify the presence of stated features, integers, steps orcomponents but does not preclude the presence or addition of one or moreother features, integers, steps, components or groups thereof.

What is claimed is:
 1. An absorbent article comprising: a surfacestructure having a liquid-permeable surface sheet located on aliquid-receiving side; a back sheet; and an absorbent core sandwichedbetween the surface structure and the back sheet, wherein, in an areaincluding at least a centerline extending in a longitudinal direction ofthe absorbent article, the surface sheet is corrugated to form recessesand ridges extending in the longitudinal direction and alternating witheach other in a transverse direction perpendicular to the longitudinaldirection, and the ridges are given an elastically shrinking function inthe longitudinal direction at least at their crests or vicinitiesthereof so that the surface structure is formed into a curved shape. 2.An absorbent article according to claim 1, wherein elastic membersextending in the longitudinal direction are attached to the crests ofthe ridges of the surface sheet to thereby give the elasticallyshrinking function.
 3. An absorbent article according to claim 2,wherein the surface structure includes a liquid-permeable support sheetlocated between the surface sheet and the absorbent core, and thesupport sheet is bonded to the surface sheet at an interval in thetransverse direction to thereby form the recesses.
 4. An absorbentarticle according to claim 3, wherein a cushion layer is provided insideof the ridges such that the cushion layer is sandwiched between thesurface sheet and the support sheet.
 5. An absorbent article accordingto claim 4, wherein ridges in a center region including thelongitudinally extending centerline are different in height from otherridges in two side regions outside of the center region.
 6. An absorbentarticle according to claim 5, wherein cover sheets are provided to coverlongitudinal end portions of the ridges.
 7. An absorbent articleaccording to claim 1, wherein the surface structure includes aliquid-permeable support sheet located between the surface sheet and theabsorbent core, and the support sheet is bonded to the surface sheet atan interval in the transverse direction to thereby form the recesses. 8.An absorbent article according to claim 7, wherein a cushion layer isprovided inside of the ridges such that the cushion layer is sandwichedbetween the surface sheet and the support sheet.
 9. An absorbent articleaccording to claim 8, wherein ridges in a center region including thelongitudinally extending centerline are different in height from otherridges in two side regions outside of the center region.
 10. Anabsorbent article according to claim 9, wherein cover sheets areprovided to cover longitudinal end portions of the ridges.
 11. Anabsorbent article according to claim 1, wherein ridges in a centerregion including the longitudinally extending centerline are differentin height from other ridges in two side regions outside of the centerregion.
 12. An absorbent article according to claim 2, wherein ridges ina center region including the longitudinally extending centerline aredifferent in height from other ridges in two side regions outside of thecenter region.
 13. An absorbent article according to claim 1, whereincover sheets are provided to cover longitudinal end portions of theridges.
 14. An absorbent article according to claim 2, wherein coversheets are provided to cover longitudinal end portions of the ridges.